[PATCH 3/7] clk: sunxi-ng: de2: Export register regmap for DE33

[Jernej Skrabec <jernej.skrabec@gmail.com>]

DE33 clock pre-set plane mapping, which is not something that we want
from clock driver. Export registers instead, so DRM driver can set them
properly.

Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
---
 drivers/clk/sunxi-ng/ccu-sun8i-de2.c | 53 ++++++++++++++++++++++++++--
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-de2.c b/drivers/clk/sunxi-ng/ccu-sun8i-de2.c
index a6cd0f988859..2841ec922025 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-de2.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-de2.c
@@ -6,9 +6,11 @@
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/io.h>
+#include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/reset.h>
 
 #include "ccu_common.h"
@@ -250,6 +252,41 @@ static const struct sunxi_ccu_desc sun50i_h616_de33_clk_desc = {
 	.num_resets	= ARRAY_SIZE(sun50i_h5_de2_resets),
 };
 
+/*
+ * Add a regmap for the DE33 plane driver to access plane
+ * mapping registers.
+ * Only these registers are allowed to be written, to prevent
+ * overriding clock and reset configuration.
+ */
+
+#define SUN50I_DE33_CHN2CORE_REG 0x24
+#define SUN50I_DE33_PORT02CHN_REG 0x28
+#define SUN50I_DE33_PORT12CHN_REG 0x2c
+
+static bool sun8i_de2_ccu_regmap_accessible_reg(struct device *dev,
+						unsigned int reg)
+{
+	switch (reg) {
+	case SUN50I_DE33_CHN2CORE_REG:
+	case SUN50I_DE33_PORT02CHN_REG:
+	case SUN50I_DE33_PORT12CHN_REG:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config sun8i_de2_ccu_regmap_config = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+	.max_register	= 0xe0,
+
+	/* other devices have no business accessing other registers */
+	.readable_reg	= sun8i_de2_ccu_regmap_accessible_reg,
+	.writeable_reg	= sun8i_de2_ccu_regmap_accessible_reg,
+};
+
 static int sunxi_de2_clk_probe(struct platform_device *pdev)
 {
 	struct clk *bus_clk, *mod_clk;
@@ -303,13 +340,23 @@ static int sunxi_de2_clk_probe(struct platform_device *pdev)
 	}
 
 	/*
-	 * The DE33 requires these additional (unknown) registers set
+	 * The DE33 requires these additional plane mapping registers set
 	 * during initialisation.
 	 */
 	if (of_device_is_compatible(pdev->dev.of_node,
 				    "allwinner,sun50i-h616-de33-clk")) {
-		writel(0, reg + 0x24);
-		writel(0x0000a980, reg + 0x28);
+		struct regmap *regmap;
+
+		regmap = devm_regmap_init_mmio(&pdev->dev, reg,
+					       &sun8i_de2_ccu_regmap_config);
+		if (IS_ERR(regmap)) {
+			ret = PTR_ERR(regmap);
+			goto err_assert_reset;
+		}
+
+		ret = of_syscon_register_regmap(pdev->dev.of_node, regmap);
+		if (ret)
+			goto err_assert_reset;
 	}
 
 	ret = devm_sunxi_ccu_probe(&pdev->dev, reg, ccu_desc);
-- 
2.51.2